Changing technology and methods of use. Older studies evaluated radiofrequency radiation exposure from analog cell phones. Today, cell phones use digital technology, which operates at a different frequency and a lower power level than analog phones. Digital cell phones have been in use for more than two decades in the United States, and cellular technology continues to change (3). Texting and other applications, for example, are common uses of cell phones that do not require bringing the phone close to the head. Furthermore, the use of hands-free technology, such as wired and wireless headsets, is increasing and may reduce exposure by distancing the phone from the body (36, 37).

RF waves from cell phones have also been shown to produce “stress” proteins in human cells, according to research from Martin Blank, Ph.D., a special lecturer in the department of physiology and cellular biophysics at Columbia University and another signer of the recent letter to the WHO and U.N. “These proteins are used for protection,” Blank says. “The cell is saying that RF is bad for me and it has to do something about it.”

We really do not recommend any kind of chip, guard, anti-radiation "filters" or incomplete shielding case because honestly, how could they NOT provide a false sense of security? Folks could believe these products make them “invincible” against radiation so they are comfortable holding the case right up to their heads-and the radiation seeping from the back and the side of the phone case is in very close proximity to their precious brains. Oh no!
Forward your cell phone to landlines whenever you are at home, then power off the cell phone without missing a call. Biological effects can be related to both strength of cell phone radiation dose and duration of exposure, so consider whether or not your communication is urgent. Remember: Use a corded home landline (not a home cordless phone, because cordless phones use electromagnetic microwave technology just like cell phones). Most cordless phone base stations constantly emit microwave radiation regardless whether or not any connected handset is in use. The cordless phone handsets also emit microwave radiation. Corded landlines have no radiation emissions and are the best choice.

Jump up ^ For example, Finland "Radiation and Nuclear Safety Authority: Children's mobile phone use should be limited". Finnish Radiation and Nuclear Safety Authority (STUK). 7 January 2009. Archived from the original on 11 January 2010. Retrieved 20 January 2010. and France "Téléphone mobile, DAS et santé" [Mobile telephones, SAR and health] (PDF). Votre enfant et le téléphone mobile [Your child and mobile telephony]. Association Française des Opérateurs Mobiles (AFOM)[French Mobile Phone Operators' Association] et l’Union Nationale des Associations Familiales (UNAF) [National Federation of Family Associations]. 31 January 2007. Retrieved 20 January 2010.
Generally speaking, the near-field refers to the RF field close to the antenna and the far-field is the RF field further away from the antenna. Often times when you use your cell phone, your body is often located in the near-field (one wavelength or less) of the cell phone antenna. It is especially concerning when you hold your phone next to your head or wear it on your body as you can be exposed to very intense near-field radiation from the phone.
Radiofrequency radiation is a form of electromagnetic radiation. Electromagnetic radiation can be categorized into two types: ionizing (e.g., x-rays, radon, and cosmic rays) and non-ionizing (e.g., radiofrequency and extremely low frequency, or power frequency). Electromagnetic radiation is defined according to its wavelength and frequency, which is the number of cycles of a wave that pass a reference point per second. Electromagnetic frequencies are described in units called hertz (Hz).